1. Field of the Invention
This invention relates to stationery materials and office supplies, and specifically to envelopes which are to be sent to a large number of addresses, which may bear other personalized indications apart from addresses, and which are printed by the printing unit of a computer or of electrical counting equipment or the like.
2. Discussion of Background and Material Information
When a document, referred to hereinafter as a "folded sheet" or "insert", to be wrapped or enclosed in an envelope has sufficiently small dimensions, the format of the folded sheet is at most equal to the envelope format. In this case, the document sheet can be stacked at the time of manufacture as a continuous band together with two other bands which are intended to constitute respectively the top and bottom faces of the envelopes. The resultant continuous assembly of folded sheets, referred to herein as "mailers", are thus adapted for use in a conventional printing machine installed on the premises of the user which prints through the top band or layer of paper by means of conventional expedients, i.e., carbon zones, chemical papers, self-reproducers, and the like.
Alternatively, the assembly of bands may be performed on the premises of the user after passing the band of inserts through a printing machine such as the one described in French Application No. 76 29415, published as French Pat. No. 2,326,249, commonly owned with the present application.
It is also possible to form unitized inserts from the inserts on the premises of the user, which are adhesively bonded to the continuous band which is intended to form a back of the envelope as contemplated in French Application No. 75 27578, published as French Pat. No. 2,323,612, commonly owned with the present application, or as disclosed in U.S. Pat. No. 4,095,695.
Finally, with an insert which is slightly smaller than the envelope both in height and in width, unitization of inserts can be carried out on the premises of the user after printing and prior to insertion between the two bands constituting the front and rear faces of the envelope in accordance with a method which forms the subject of European Pat. No. 0,051,099, commonly owned with the present application. In the case just mentioned, it is possible prior to unitization of the inserts to fold the band of inserts in their longitudinal direction in half as stated in the patent cited above. In this case, each insert has a width greater than that of the envelope but remains of smaller height.
When the area of the insert is intended to be twice that of its envelope, the only means and methods presently known to accomplish this end involve the use of a conventional plate-type reciprocating or rotary folding machine followed by a pocket-forming machine after unitization of the inserts. However, although the transfer of the band of inserts within the printing machine can take place in increasingly higher speeds, i.e., up to 2400 m/h, the folding and pocket-forming operation cannot attain one-half this speed even with machines which are capable of the highest performances. It is consequently necessary to provide a plurality of these machines.